LACs (that I know of) that attract a high percentage of math majors:
Harvey Mudd: 14%
Williams: 13%
Hamilton: 10%
Bowdoin: 9%
Pomona: 9%
Simply perusing the course offerings at these schools should give you an idea as to whether they would be suitable for you in relation to your current level. A semester in Budapest from any of these schools is another way to pursue even greater mathematical depth during your undergraduate years.